Composition for forming resist underlayer film and pattern-forming method

ABSTRACT

A composition for forming a resist underlayer film includes a polysiloxane and a solvent. The solvent includes an organic solvent having a standard boiling point of no less than 150.0° C., and water. A content of the organic solvent is no less than 1% by mass and no greater than 50% by mass with respect to a total amount of the solvent. A content of water is no less than 1% by mass and no greater than 30% by mass with respect to the total amount of the solvent.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2012-050956, filed Mar. 7, 2012 and to JapanesePatent Application No. 2013-016155, filed Jan. 30, 2013. The contents ofthese applications are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a composition for forming a resistunderlayer film, and a pattern-forming method.

2. Discussion of the Background

In manufacturing semiconductor devices, multilayer resist processes havebeen employed for attaining a high degree of integration. In theseprocesses, a composition for forming a resist underlayer film is firstcoated on a substrate to provide a resist underlayer film, and then aresist composition is coated on the resist underlayer film to provide aresist film. Thereafter, a resist film is exposed through a mask patternby means of a stepping projection aligner (stepper) or the like, anddeveloped with an appropriate developer solution to form a resistpattern. Subsequently, the resist underlayer film is dry-etched usingthe resist pattern as a mask, and the substrate is further dry-etchedusing the resultant resist underlayer film pattern as a mask, therebyenabling a desired pattern to be formed on the substrate.

In recent years, in order to further increase the degree of integration,miniaturization of patterns has been further in progress. Also inconnection with the multilayer resist processes described above,structures of polymers, etc., contained in the composition for forming aresist underlayer film, and functional groups included in the polymershave been variously investigated. For resist underlayer films proposedso far, a composition for forming a resist underlayer film containing ahydrolytic condensate of a compound that includes a certain hydrolyzablesilane compound, and the like are exemplified (see Japanese UnexaminedPatent Application, Publication No. 2002-40668).

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a composition forforming a resist underlayer film includes a polysiloxane and a solvent.The solvent includes an organic solvent having a standard boiling pointof no less than 150.0° C., and water. A content of the organic solventis no less than 1% by mass and no greater than 50% by mass with respectto a total amount of the solvent. A content of water is no less than 1%by mass and no greater than 30% by mass with respect to the total amountof the solvent.

According to another aspect of the present invention, a pattern-formingmethod includes providing a resist underlayer film on a substrate usingthe composition. A resist film is provided on the resist underlayer filmusing a resist composition. The resist film is exposed by irradiationwith a radioactive ray through a mask. The exposed resist film isdeveloped to form a resist pattern. The resist underlayer film and thesubstrate are sequentially dry-etched using the resist pattern as amask.

DESCRIPTION OF THE EMBODIMENTS

An aspect of the embodiment of the present invention made for solvingthe foregoing problems provides a composition for forming a resistunderlayer film that includes:

a polysiloxane (hereinafter, may be also referred to as “polysiloxane(A)”); and

a solvent (hereinafter, may be also referred to as “solvent (B)”),

wherein the solvent includes:

an organic solvent having a standard boiling point of no less than150.0° C. (hereinafter, may be also referred to as “organic solvent(B1)”); and

water (hereinafter, may be also referred to as “water (B2)”), and

wherein the content of the organic solvent is no less than 1% by massand no greater than 50% by mass with respect to the total amount of thesolvent, and

the content of water is no less than 1% by mass and no greater than 30%by mass with respect to the total amount of the solvent.

When the solvent (B) includes the organic solvent (B1) and the water(B2) at a content falling within a specified range described above, thecomposition for forming a resist underlayer film can exhibit a superiorinhibitory property of coating defects, and storage stability, i.e., anincrease of coating defects, alteration of the film thickness of aresultant coated film, and the like are less likely to occur even afterstorage for a long period of time. Although the reasons for achievingsuch effects by the solvent (B) constituted as described above are notnecessarily clear, it is envisaged, for example, that due to containingthe organic solvent (B1) that is a high-boiling point solvent, andcontaining the water (B2) in a given quantity or more, volatilization ofa solvent in a nozzle during coating, and the like can be suppressed,thereby enabling generation of coating defects to be inhibited, andmodification of silanol groups included in the composition for forming aresist underlayer film to be suppressed, leading to improvement of thestorage stability.

The standard boiling point of the organic solvent (B1) is preferably noless than 180° C. When the standard boiling point of the organic solvent(B1) falls within the range specified above, the composition for forminga resist underlayer film can attain an improved inhibitory property ofcoating defects, and storage stability.

The organic solvent (B1) is preferably an ester, an alcohol, an ether ora combination thereof. When the organic solvent (B1) is the solventspecified above, the composition for forming a resist underlayer filmcan attain an improved inhibitory property of coating defects, andstorage stability.

The organic solvent (B1) is preferably a lactone, a carbonate, acompound represented by the following formula (B-1) or a combinationthereof. When the organic solvent (B1) is the solvent specified above,the composition for forming a resist underlayer film can attain animproved inhibitory property of coating defects, and storage stability.

In the formula (B-1), R¹ and R² each independently represent a hydrogenatom, an alkyl group having 1 to 4 carbon atoms or an acyl group having1 to 4 carbon atoms; R³ represents a hydrogen atom or a methyl group; nis an integer of 1 to 4, in a case where R³ is present in a plurality ofnumber, a plurality of R³s are each optionally the same or different.

The relative permittivity of the organic solvent (B1) is preferably 13or greater and 200 or less. relative permittivity of the organic solvent(B1) falls within the range specified above, the composition for forminga resist underlayer film can attain an improved inhibitory property ofcoating defects, and storage stability.

It is preferred that the solvent (B) further includes (B3) an alcoholother than the organic solvent described above (hereinafter, may be alsoreferred to as “alcohol (B3)”). Accordingly, the composition for forminga resist underlayer film can attain an improved inhibitory property ofcoating defects, and storage stability.

It is preferred that the composition for forming a resist underlayerfilm further includes (C) an acid diffusion controller. Accordingly, thecomposition for forming a resist underlayer film enables diffusion of anacid from a resist film via the resist underlayer film to be inhibitedwhile maintaining the effects described above, whereby patterndevelopability and the like can be improved.

The polysiloxane (A) is preferably a hydrolytic condensate of a compoundthat includes a hydrolyzable silane compound represented by thefollowing formula (i) (hereinafter, may be also referred to as “compound(i)”).

R^(A) _(a)SiX_(4-a)  (i)

In the formula (i), R^(A) represents a hydrogen atom, a fluorine atom,an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to10 carbon atoms, an aryl group having 6 to 20 carbon atoms or a cyanogroup, wherein a part or all of hydrogen atoms included in the alkylgroup are not substituted or optionally substituted by an epoxyalkyloxygroup, an epoxy group, an acid anhydride group or a cyano group, and apart or all of hydrogen atoms included in the aryl group are notsubstituted or optionally substituted by a hydroxy group; X represents ahalogen atom or —OR^(B), wherein R^(B) represents a monovalent organicgroup; a is an integer of 0 to 3, wherein in a case where R^(A) and Xare each present in a plurality of number, each of a plurality of R^(A)sand a plurality of Xs are each optionally the same or different.

When a hydrolytic condensate of a compound that includes the compound(i) is thus used as the polysiloxane (A), the composition for forming aresist underlayer film can attain an improved inhibitory property ofcoating defects, and storage stability.

The composition for forming a resist underlayer film of the embodimentof the present invention is suitably used in multilayer resistprocesses. The composition for forming a resist underlayer film issuperior in the inhibitory property of coating defects, and storagestability.

Moreover, a pattern-forming method according to another aspect of theembodiment of the present invention includes:

providing a resist underlayer film on a substrate using the compositionfor forming a resist underlayer film;

providing a resist film on the resist underlayer film using a resistcomposition;

exposing the resist film by irradiation with a radioactive ray through amask;

developing the exposed resist film to form a resist pattern; and

sequentially dry-etching the resist underlayer film and the substrateusing the resist pattern as a mask.

Since the composition for forming a resist underlayer film of theembodiment of the present invention is used in the pattern-formingmethod, a resist underlayer film that is superior in the inhibitoryproperty of coating defects can be provided. In addition, even if thecomposition for forming a resist underlayer film which had been storedfor a long period of time is used, favorable patterns can be obtained.Therefore, the pattern-forming method according to the embodiment of thepresent invention is responsible for formation of a finer pattern on asubstrate.

The term “organic group” as referred to herein means a group thatincludes at least one carbon atom. Herein, the “relative permittivity”as referred to means a ratio of the dielectric constant of the organicsolvent (B1) to the dielectric constant of a vacuum measured at 20° C.It is to be noted that with respect to the relative permittivity of theorganic solvent (B1), a value described in “Chemical Handbook: BasicEdition; Revised 5th Edition”, etc., may be referred to. Also, as therelative permittivity of the organic solvent (B1) not listed in theChemical Handbook, a value obtained by determining at 20° C. by a methoddescribed in JIS C2138 may be referred to.

The composition for forming a resist underlayer film of the embodimentof the present invention is superior in an inhibitory property ofcoating defects, and storage stability. Therefore, the composition forforming a resist underlayer film and pattern-forming method can besuitably used in lithography processes for which further miniaturizationis desired. The embodiments will now be described in detail.

Composition for Forming a Resist Underlayer Film

The composition for forming a resist underlayer film of the embodimentof the present invention contains (A) a polysiloxane and (B) a solvent.In addition, the composition for forming a resist underlayer film maycontain (C) an acid diffusion controller as a suitable component.Furthermore, the composition for forming a resist underlayer film maycontain other optional component as long as the effects of the presentinvention are not impaired. Hereinafter, each component will beexplained in detail.

(A) Polysiloxane

The polysiloxane (A) is not particularly limited as long as it is apolymer having a siloxane bond, and is preferably a hydrolyticcondensate of a compound that includes the hydrolyzable silane compoundrepresented by the above formula (i). The hydrolyzable silane compoundused in the synthesis of the polysiloxane (A) may be used either aloneof one type, or in combination of two or more types thereof.

In the formula (i), R^(A) represents a hydrogen atom, a fluorine atom,an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to10 carbon atoms, an aryl group having 6 to 20 carbon atoms or a cyanogroup, wherein a part or all of hydrogen atoms included in the alkylgroup are not substituted or optionally substituted by an epoxyalkyloxygroup, an epoxy group, an acid anhydride group or a cyano group, and apart or all of hydrogen atoms included in the aryl group are notsubstituted or optionally substituted by a hydroxy group; X represents ahalogen atom or —OR^(B), wherein R^(B) represents a monovalent organicgroup; a is an integer of 0 to 3, wherein in a case where R^(A) and Xare each present in a plurality of number, each of a plurality of R^(A)sand a plurality of Xs are each optionally the same or different.

Examples of the alkyl group having 1 to 5 carbon atoms represented bythe R^(A) include linear alkyl groups such as a methyl group, an ethylgroup, a n-propyl group, a n-butyl group and a n-pentyl group; branchedalkyl groups such as an isopropyl group, an isobutyl group, a sec-butylgroup, a t-butyl group and an isoamyl group, and the like. Of these,linear alkyl groups are preferred, and a methyl group is more preferred.

The alkenyl group represented by the R^(A) is exemplified by groupsderived by removing one hydrogen atom from an alkene compound and thelike, and examples thereof include an ethenyl group, a 1-propen-1-ylgroup, a 1-propen-2-yl group, a 1-propen-3-yl group, a 1-buten-1-ylgroup, a 1-buten-2-yl group, a 1-buten-3-yl group, a 1-buten-4-yl group,a 2-buten-1-yl group, a 2-buten-2-yl group, a 1-penten-5-yl group, a2-penten-1-yl group, a 2-penten-2-yl group, a 1-hexen-6-yl group, a2-hexen-1-yl group, a 2-hexen-2-yl group, and the like.

Examples of the aryl group represented by the R^(A) include a phenylgroup, a naphthyl group, a methylphenyl group, an ethylphenyl group, achlorophenyl group, a bromophenyl group, a fluorophenyl group, and thelike. Of these, a phenyl group and a methylphenyl group are preferred.It is to be noted that the aryl group includes aralkyl groups accordingto the concept herein.

The “epoxy group” in the epoxyalkyloxy group may involve an oxiranylgroup and an oxetanyl group, and the epoxyalkyloxy group with which thealkyl group may be substituted is exemplified by a glycidyloxy group, anoxetanylmethyloxy group, and the like.

The epoxy group with which the alkyl group may be substituted isexemplified by an oxiranyl group, an oxetanyl group, and the like.

The acid anhydride group with which the alkyl group may be substitutedis exemplified by, e.g., a succinic anhydride group, a maleic anhydridegroup, a glutaric anhydride group, and the like.

Examples of the alkyl group substituted with a glycidyloxy group includea 2-glycidyloxyethyl group, a 3-glycidyloxypropyl group, a4-glycidyloxybutyl group, and the like. Of these, a 3-glycidyloxypropylgroup is more preferred.

Examples of the alkyl group substituted with an oxetanylmethyloxy groupinclude a 3-ethyl-3-oxetanylmethyloxypropyl group, a3-methyl-3-oxetanylmethyloxypropyl group, a3-ethyl-2-oxetanylmethyloxypropyl group, a 2-oxetanylmethyloxyethylgroup, and the like. Of these, a 3-ethyl-3-oxetanylmethyloxypropyl groupis preferred.

Examples of the alkyl group substituted with an acid anhydride groupinclude a 2-succinic anhydride group-substituted ethyl group, a3-succinic anhydride group-substituted propyl group, a 4-succinicanhydride group-substituted butyl group, and the like. Of these, a3-succinic anhydride group-substituted propyl group is more preferred.

Examples of the alkyl group substituted with a cyano group include a2-cyanoethyl group, a 3-cyanopropyl group, a 4-cyanobutyl group, and thelike.

Examples of the aryl group substituted with a hydroxy group include a4-hydroxyphenyl group, a 4-hydroxy-2-methylphenyl group, a4-hydroxynaphthyl group, and the like. Of these, a 4-hydroxyphenyl groupis more preferred.

R^(A) represents preferably an alkyl group or an aryl group.

Examples of the halogen atom represented by X include a fluorine atom, achlorine atom, a bromine atom, an iodine atom, and the like.

As the monovalent organic group represented by the R^(B), an alkylgroup, an alkylcarbonyl group and the like may be exemplified. The alkylgroup is preferably a methyl group, an ethyl group, a n-propyl group, anisopropyl group, a n-butyl group, a isobutyl group, a sec-butyl group ora t-butyl group, and more preferably a methyl group. In addition, as thealkylcarbonyl group, a methylcarbonyl group and an ethylcarbonyl groupare preferred.

R^(B) represents preferably an alkyl group.

“a” is preferably an integer of 0 to 2, and more preferably 0 or 1.

Specific examples of the hydrolyzable silane compound represented by theabove formula (i) include:

aromatic ring-containing trialkoxysilanes such asphenyltrimethoxysilane, 4-methylphenyltrimethoxysilane,4-ethylphenyltrimethoxysilane, 4-hydroxyphenyltrimethoxysilane,3-methylphenyltrimethoxysilane, 3-ethylphenyltrimethoxysilane,3-hydroxyphenyltrimethoxysilane, 2-methylphenyltrimethoxysilane,2-ethylphenyltrimethoxysilane, 2-hydroxyphenyltrimethoxysilane and2,4,6-trimethylphenyltrimethoxysilane;

alkyltrialkoxysilanes such as methyltrimethoxysilane,methyltriethoxysilane, methyltri-n-propoxysilane,methyltri-iso-propoxysilane, methyltri-n-butoxysilane,methyltri-sec-butoxysilane, methyltri-t-butoxysilane,methyltriphenoxysilane, methyltriacetoxysilane, methyltrichlorosilane,methyltriisopropenoxysilane, methyltris(dimethylsiloxy)silane,methyltris(methoxyethoxy)silane, methyltris(methylethylketoxime)silane,methyltris(trimethylsiloxy)silane, methylsilane, ethyltrimethoxysilane,ethyltriethoxysilane, ethyltri-n-propoxysilane,ethyltri-iso-propoxysilane, ethyltri-n-butoxysilane,ethyltri-sec-butoxysilane, ethyltri-t-butoxysilane,ethyltriphenoxysilane, ethylbistris(trimethylsiloxy)silane,ethyldichlorosilane, ethyltriacetoxysilane, ethyltrichlorosilane,n-propyltrimethoxysilane, n-propyltriethoxysilane,n-propyltri-n-propoxysilane, n-propyltri-iso-propoxysilane,n-propyltri-n-butoxysilane, n-propyltri-sec-butoxysilane,n-propyltri-t-butoxysilane, n-propyltriphenoxysilane,n-propyltriacetoxysilane, n-propyltrichlorosilane,iso-propyltrimethoxysilane, iso-propyltriethoxysilane,iso-propyltri-n-propoxysilane, iso-propyltri-iso-propoxysilane,iso-propyltri-n-butoxysilane, iso-propyltri-sec-butoxysilane,iso-propyltri-t-butoxysilane, iso-propyltriphenoxysilane,n-butyltrimethoxysilane, n-butyltriethoxysilane,n-butyltri-n-propoxysilane, n-butyltri-iso-propoxysilane,n-butyltri-n-butoxysilane, n-butyltri-sec-butoxysilane,n-butyltri-t-butoxysilane, n-butyltriphenoxysilane,n-butyltrichlorosilane, 2-methylpropyltrimethoxysilane,2-methylpropyltriethoxysilane, 2-methylpropyltri-n-propoxysilane,2-methylpropyltri-iso-propoxysilane, 2-methylpropyltri-n-butoxysilane,2-methylpropyltri-sec-butoxysilane, 2-methylpropyltri-t-butoxysilane,2-methylpropyltriphenoxysilane, 1-methylpropyltrimethoxysilane,1-methylpropyltriethoxysilane, 1-methylpropyltri-n-propoxysilane,1-methylpropyltri-iso-propoxysilane, 1-methylpropyltri-n-butoxysilane,1-methylpropyltri-sec-butoxysilane, 1-methylpropyltri-t-butoxysilane,1-methylpropyltriphenoxysilane, t-butyltrimethoxysilane,t-butyltriethoxysilane, t-butyltri-n-propoxysilane,t-butyltri-iso-propoxysilane, t-butyltri-n-butoxysilane,t-butyltri-sec-butoxysilane, t-butyltri-t-butoxysilane,t-butyltriphenoxysilane, t-butyltrichlorosilane andt-butyldichlorosilane;

alkenyltrialkoxysilanes such as vinyltrimethoxysilane,vinyltriethoxysilane, vinyltri-n-propoxysilane,vinyltriisopropoxysilane, vinyltri-n-butoxysilane,vinyltri-sec-butoxysilane, vinyltri-t-butoxysilane,vinyltriphenoxysilane, allyltrimethoxysilane, allyltriethoxysilane,allyltri-n-propoxysilane, allyltriisopropoxysilane,allyltri-n-butoxysilane, allyltri-sec-butoxysilane,allyltri-t-butoxysilane and allyltriphenoxysilane;

-   -   tetraalkoxysilanes such as tetramethoxysilane,        tetraethoxysilane, tetra-n-propoxysilane,        tetra-iso-propoxysilane, tetra-n-butoxysilane,        tetra-sec-butoxysilane and tetra-t-butoxysilane;

tetraarylsilanes such as tetraphenoxysilane;

epoxy group-containing silanes such as oxetanyltrimethoxysilane,oxiranyltrimethoxysilane, oxiranylmethyltrimethoxysilane and3-glycidyloxypropyltrimethoxysilane;

acid anhydride group-containing silanes such as3-(trimethoxysilyl)propylsuccinic anhydride,2-(trimethoxysilyl)ethylsuccinic anhydride,3-(trimethoxysilyl)propylmaleic anhydride and2-(trimethoxysilyl)ethylglutaric anhydride; tetrahalosilanes such astetrachlorosilane; and the like.

Of these, tetramethoxysilane, phenyltrimethoxysilane, 4-smethylphenyltrimethoxysilane, and methyltrimethoxysilane are preferred.

For the synthesis of the polysiloxane (A), in addition to thehydrolyzable silane compound represented by the above formula (i), othersilane compound may be used such as, for example,

disilanes such as hexamethoxydisilane, hexaethoxydisilane,hexaphenoxydisilane, 1,1,1,2,2-pentamethoxy-2-methyldisilane,1,1,1,2,2-pentaethoxy-2-methyldisilane,1,1,1,2,2-pentaphenoxy-2-methyldisilane,1,1,1,2,2-pentamethoxy-2-ethyldisilane,1,1,1,2,2-pentaethoxy-2-ethyldisilane,1,1,1,2,2-pentaphenoxy-2-ethyldisilane,1,1,1,2,2-pentamethoxy-2-phenyldisilane,1,1,1,2,2-pentaethoxy-2-phenyldisilane,1,1,1,2,2-pentaphenoxy-2-phenyldisilane,1,1,2,2-tetramethoxy-1,2-dimethyldisilane,1,1,2,2-tetraethoxy-1,2-dimethyldisilane,1,1,2,2-tetraphenoxy-1,2-dimethyldisilane,1,1,2,2-tetramethoxy-1,2-diethyldisilane,1,1,2,2-tetraethoxy-1,2-diethyldisilane,1,1,2,2-tetraphenoxy-1,2-diethyldisilane,1,1,2,2-tetramethoxy-1,2-diphenyldisilane,1,1,2,2-tetraethoxy-1,2-diphenyldisilane,1,1,2,2-tetraphenoxy-1,2-diphenyldisilane,1,1,2-trimethoxy-1,2,2-trimethyldisilane,1,1,2-triethoxy-1,2,2-trimethyldisilane,1,1,2-triphenoxy-1,2,2-trimethyldisilane,1,1,2-trimethoxy-1,2,2-triethyldisilane,1,1,2-triethoxy-1,2,2-triethyldisilane,1,1,2-triphenoxy-1,2,2-triethyldisilane,1,1,2-trimethoxy-1,2,2-triphenyldisilane,1,1,2-triethoxy-1,2,2-triphenyldisilane,1,1,2-triphenoxy-1,2,2-triphenyldisilane,1,2-dimethoxy-1,1,2,2-tetramethyldisilane,1,2-diethoxy-1,1,2,2-tetramethyldisilane,1,2-diphenoxy-1,1,2,2-tetramethyldisilane,1,2-dimethoxy-1,1,2,2-tetraethyldisilane,1,2-diethoxy-1,1,2,2-tetraethyldisilane,1,2-diphenoxy-1,1,2,2-tetraethyldisilane,1,2-dimethoxy-1,1,2,2-tetraphenyldisilane,1,2-diethoxy-1,1,2,2-tetraphenyldisilane,1,2-diphenoxy-1,1,2,2-tetraphenyldisilane,

bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane,bis(tri-n-propoxysilyl)methane, bis(tri-isopropoxysilyl)methane,bis(tri-n-butoxysilyl)methane, bis(tri-sec-butoxysilyl)methane,bis(tri-t-butoxysilyl)methane, 1,2-bis(trimethoxysilyl)ethane,1,2-bis(triethoxysilyl)ethane, 1,2-bis(tri-n-propoxysilyl)ethane,1,2-bis(tri-isopropoxysilyl)ethane, 1,2-bis(tri-n-butoxysilyl)ethane,1,2-bis(tri-sec-butoxysilyl)ethane, 1,2-bis(tri-t-butoxysilyl)ethane,1-(dimethoxymethylsilyl)-1-(trimethoxysilyl)methane,1-(diethoxymethylsilyl)-1-(triethoxysilyl)methane,1-(di-n-propoxymethylsilyl)-1-(tri-n-propoxysilyl)methane,1-(di-isopropoxymethylsilyl)-1-(tri-isopropoxysilyl)methane,1-(di-n-butoxymethylsilyl)-1-(tri-n-butoxysilyl)methane,1-(di-sec-butoxymethylsilyl)-1-(tri-sec-butoxysilyl)methane,1-(di-t-butoxymethylsilyl)-1-(tri-t-butoxysilyl)methane,1-(dimethoxymethylsilyl)-2-(trimethoxysilyl)ethane,1-(diethoxymethylsilyl)-2-(triethoxysilyl)ethane,1-(di-n-propoxymethylsilyl)-2-(tri-n-propoxysilyl)ethane,1-(di-isopropoxymethylsilyl)-2-(tri-isopropoxysilyl)ethane,1-(di-n-butoxymethylsilyl)-2-(tri-n-butoxysilyl)ethane,1-(di-sec-butoxymethylsilyl)-2-(tri-sec-butoxysilyl)ethane,1-(di-t-butoxymethylsilyl)-2-(tri-t-butoxysilyl)ethane,

bis(dimethoxymethylsilyl)methane, bis(diethoxymethylsilyl)methane,bis(di-n-propoxymethylsilyl)methane,bis(di-isopropoxymethylsilyl)methane,bis(di-n-butoxymethylsilyl)methane,bis(di-sec-butoxymethylsilyl)methane,bis(di-t-butoxymethylsilyl)methane, 1,2-bis(dimethoxymethylsilyl)ethane,1,2-bis(diethoxymethylsilyl)ethane,1,2-bis(di-n-propoxymethylsilyl)ethane,1,2-bis(di-isopropoxymethylsilyl)ethane,1,2-bis(di-n-butoxymethylsilyl)ethane,1,2-bis(di-sec-butoxymethylsilyl)ethane,1,2-bis(di-t-butoxymethylsilyl)ethane, bis(dimethylmethoxysilyl)methane,bis(dimethylethoxysilyl)methane, bis(dimethyl-n-propoxysilyl)methane,bis(dimethyl-isopropoxysilyl)methane,bis(dimethyl-n-butoxysilyl)methane,bis(dimethyl-sec-butoxysilyl)methane,bis(dimethyl-t-butoxysilyl)methane, 1,2-bis(dimethylmethoxysilyl)ethane,1,2-bis(dimethylethoxysilyl)ethane,1,2-bis(dimethyl-n-propoxysilyl)ethane,1,2-bis(dimethyl-isopropoxysilyl)ethane,1,2-bis(dimethyl-n-butoxysilyl)ethane,1,2-bis(dimethyl-sec-butoxysilyl)ethane,1,2-bis(dimethyl-t-butoxysilyl)ethane,

1-(dimethoxymethylsilyl)-1-(trimethylsilyl)methane,1-(diethoxymethylsilyl)-1-(trimethylsilyl)methane,1-(di-n-propoxymethylsilyl)-1-(trimethylsilyl)methane,1-(di-isopropoxymethylsilyl)-1-(trimethylsilyl)methane,1-(di-n-butoxymethylsilyl)-1-(trimethylsilyl)methane,1-(di-sec-butoxymethylsilyl)-1-(trimethylsilyl)methane,1-(di-t-butoxymethylsilyl)-1-(trimethylsilyl)methane,1-(dimethoxymethylsilyl)-2-(trimethylsilyl)ethane,1-(diethoxymethylsilyl)-2-(trimethylsilyl)ethane,1-(di-n-propoxymethylsilyl)-2-(trimethylsilyl)ethane,1-(di-isopropoxymethylsilyl)-2-(trimethylsilyl)ethane,1-(di-n-butoxymethylsilyl)-2-(trimethylsilyl)ethane,1-(di-sec-butoxymethylsilyl)-2-(trimethylsilyl)ethane,1-(di-t-butoxymethylsilyl)-2-(trimethylsilyl)ethane,1,2-bis(trimethoxysilyl)benzene, 1,2-bis(triethoxysilyl)benzene,1,2-bis(tri-n-propoxysilyl)benzene, 1,2-bis(tri-isopropoxysilyl)benzene,1,2-bis(tri-n-butoxysilyl)benzene, 1,2-bis(tri-sec-butoxysilyl)benzene,1,2-bis(tri-t-butoxysilyl)benzene, 1,3-bis(trimethoxysilyl)benzene,1,3-bis(triethoxysilyl)benzene, 1,3-bis(tri-n-propoxysilyl)benzene,1,3-bis(tri-isopropoxysilyl)benzene, 1,3-bis(tri-n-butoxysilyl)benzene,1,3-bis(tri-sec-butoxysilyl)benzene, 1,3-bis(tri-t-butoxysilyl)benzene,1,4-bis(trimethoxysilyl)benzene, 1,4-bis(triethoxysilyl)benzene,1,4-bis(tri-n-propoxysilyl)benzene, 1,4-bis(tri-isopropoxysilyl)benzene,1,4-bis(tri-n-butoxysilyl)benzene, 1,4-bis(tri-sec-butoxysilyl)benzeneand 1,4-bis(tri-t-butoxysilyl)benzene;

polycarbosilanes such as polydimethoxymethylcarbosilane andpolydiethoxymethylcarbosilane; and

benzyltrimethoxysilane, phenethyltrimethoxysilane, 4-smethoxyphenyltrimethoxysilane, 4-phenoxyphenyltrimethoxysilane,4-aminophenyltrimethoxysilane, 4-dimethylaminophenyltrimethoxysilane,4-acetylaminophenyltrimethoxysilane, 3-methoxyphenyltrimethoxysilane,3-phenoxyphenyltrimethoxysilane, 3-aminophenyltrimethoxysilane,3-dimethylaminophenyltrimethoxysilane,3-acetylaminophenyltrimethoxysilane, 2-methoxyphenyltrimethoxysilane,2-phenoxyphenyltrimethoxysilane, 2-aminophenyltrimethoxysilane,2-dimethylaminophenyltrimethoxysilane,2-acetylaminophenyltrimethoxysilane, 4-methylbenzyltrimethoxysilane,4-ethylbenzyltrimethoxysilane, 4-methoxybenzyltrimethoxysilane,4-phenoxybenzyltrimethoxysilane, 4-hydroxybenzyltrimethoxysilane,4-aminobenzyltrimethoxysilane, 4-dimethylaminobenzyltrimethoxysilane,and 4-acetylaminobenzyltrimethoxysilane.

For hydrolytic condensation of the compound that includes thehydrolyzable silane compound represented by the above formula (i) andother silane compound which may be used as needed, well-known methodsfor hydrolytic condensation may be employed.

The content of the polysiloxane (A) in the composition for forming aresist underlayer film is preferably no less than 50% by mass, and morepreferably no less than 55% by mass with respect to the total solidcontent (components excluding the solvent (B)) in the composition forforming a resist underlayer film.

With respect to the molecular weight of the polysiloxane (A),polystyrene equivalent weight average molecular weight (Mw) asdetermined on gel permeation chromatography (GPC) is typically 500 to50,000, preferably 1,000 to 30,000, more preferably 1,000 to 15,000, andstill more preferably 1,000 to 10,000.

The Mw herein was determined by gel permeation chromatography (GPC) onthe basis of mono-dispersed polystyrene as a standard using GPC columnsmanufactured by Tosoh Corporation (“G2000HXL”×2; “G3000HXL”×1; and“G4000HXL”×1) under an analytical condition involving a flow rate of 1.0mL/min and a column temperature of 40° C. with tetrahydrofuran as anelution solvent.

(B) Solvent

The solvent (B) includes (B1) an organic solvent in an amount of no lessthan 1% by mass and no greater than 50% by mass with respect to thetotal amount of the solvent (B), and (B2) water in an amount of no lessthan 1% by mass and no greater than 30% by mass with respect to thetotal amount of the solvent (B). In addition, it is preferred that thesolvent (B) further includes (B3) an alcohol. Moreover, the solvent (B)may include (B4) an other solvent in addition to the organic solvent(B1), the water (B2) and the alcohol (B3).

(B1) Organic Solvent

The organic solvent (B1) has a standard boiling point of no less than150.0° C., and the content is no less than 1% by mass and no greaterthan 50% by mass with respect to the total amount of the solvent (B).Due to the solvent (B) including the organic solvent (B1) in an amountfalling within the range specified above, volatilization of a solvent ina nozzle during coating, and the like can be prevented, wherebygeneration of coating defects can be suppressed.

The standard boiling point of the organic solvent (B1) is preferably noless than 160° C., more preferably no less than 170° C., and still morepreferably no less than 180° C. When the standard boiling point of theorganic solvent (B1) falls within the above range, volatilization of asolvent in a nozzle during coating, and the like can be furtherprevented, and generation of coating defects can be further suppressed.

The standard boiling point of the organic solvent (B1) is preferably nogreater than 300° C., more preferably no greater than 280° C., stillmore preferably no greater than 250° C., and particularly preferably nogreater than 220° C.

The relative permittivity of the organic solvent (B1) is preferably 13or greater and 200 or less, more preferably 15 or greater and 150 orless, and still more preferably 20 or greater and 100 or less.

When the relative permittivity of the organic solvent (B1) falls withinthe above range, the composition for forming a resist underlayer filmcan attain an improved inhibitory property of coating defects, andstorage stability. It is speculated that due to the relativepermittivity of the organic solvent (B1) falling within the above range,the silanol group in the polysiloxane (A) can be stably present, wherebya condensation reaction can be inhibited.

Examples of the organic solvent (B1) having the relative permittivityfalling within the above range include ethyl acetoacetate (relativepermittivity: 16), N-methylpyrrolidone (relative permittivity: 33),N,N-dimethylacetamide (relative permittivity: 39), formamide (relativepermittivity: 111), N-ethylacetamide (relative permittivity: 135),N-methylacetamide (relative permittivity: 179), furfural (relativepermittivity: 42), propylene carbonate (relative permittivity: 63),ethylene carbonate (relative permittivity: 90), dimethyl sulfoxide(relative permittivity: 47), sulfolane (relative permittivity: 42),ethylene glycol (relative permittivity: 41), glycerol (relativepermittivity: 47), succinonitrile (relative permittivity: 63),nitrobenzene (relative permittivity: 36), γ-butyrolactone (relativepermittivity: 39), and the like.

The organic solvent (B1) is exemplified by esters, alcohols, ethers,ketones, amide solvents, and the like.

Examples of the ester include:

lactones such as β-propiolactone (boiling point: 162° C.),γ-butyrolactone (boiling point: 204° C.), γ-valerolactone (boilingpoint: 207° C.) and γ-undecalactone (boiling point: 286° C.);

carbonates such as ethylene carbonate (boiling point: 244° C.) andpropylene carbonate (boiling point: 242° C.);

3-methoxybutyl acetate (boiling point: 172° C.), 2-ethylbutyl acetate(boiling point: 160° C.), 2-ethylhexyl acetate (boiling point: 199° C.),benzyl acetate (boiling point: 212° C.), cyclohexyl acetate (boilingpoint: 172° C.), methylcyclohexyl acetate (boiling point: 201° C.),n-nonyl acetate (boiling point: 208° C.), methyl acetoacetate (boilingpoint: 169° C.), ethyl acetoacetate (boiling point: 181° C.), iso-amylpropionate (boiling point: 156° C.), diethyl oxalate (boiling point:185° C.), di-n-butyl oxalate (boiling point: 239° C.), ethyl lactate(boiling point: 151° C.), n-butyl lactate (boiling point: 185° C.),diethyl malonate (boiling point: 199° C.), dimethyl phthalate (boilingpoint: 283° C.), and the like.

Examples of the alcohol include:

monoalcohols such as 3-methoxybutanol (boiling point: 157° C.),n-hexanol (boiling point: 157° C.), n-octanol (boiling point: 194° C.),sec-octanol (boiling point: 174° C.), n-nonyl alcohol (boiling point:215° C.), n-decanol (boiling point: 228° C.), phenol (boiling point:182° C.), cyclohexanol (boiling point: 161° C.) and benzyl alcohol(boiling point: 205° C.);

polyhydric alcohols such as ethylene glycol (boiling point: 197° C.),1,2-propylene glycol (boiling point: 188° C.), 1,3-butylene glycol(boiling point: 208° C.), 2,4-pentanediol (boiling point: 201° C.),2-methyl-2,4-pentanediol (boiling point: 196° C.), 2,5-hexanediol(boiling point: 216° C.) and triethylene glycol (boiling point: 165°C.);

partially etherified polyhydric alcohols such as ethylene glycolmonobutyl ether (boiling point: 171° C.), ethylene glycol monophenylether (boiling point: 244° C.), diethylene glycol monomethyl ether(boiling point: 194° C.), diethylene glycol monoethyl ether (boilingpoint: 202° C.), triethylene glycol monomethyl ether (boiling point:249° C.), diethylene glycol monoisopropyl ether (boiling point: 207°C.), diethylene glycol monobutyl ether (boiling point: 231° C.),triethylene glycol monobutyl ether (boiling point: 271° C.), ethyleneglycol monoisobutyl ether (boiling point: 161° C.), diethylene glycolmonoisobutyl ether (boiling point: 220° C.), ethylene glycol monohexylether (boiling point: 208° C.), diethylene glycol monohexyl ether(boiling point: 259° C.), ethylene glycol mono 2-ethylhexyl ether(boiling point: 229° C.), diethylene glycol mono 2-ethylhexyl ether(boiling point: 272° C.), ethylene glycol monoallyl ether (boilingpoint: 159° C.), diethylene glycol monophenyl ether (boiling point: 283°C.), ethylene glycol monobenzyl ether (boiling point: 256° C.),diethylene glycol monobenzyl ether (boiling point: 302° C.), dipropyleneglycol monomethyl ether (boiling point: 187° C.), tripropylene glycolmonomethyl ether (boiling point: 242° C.), dipropylene glycol monopropylether (boiling point: 212° C.), propylene glycol monobutyl ether(boiling point: 170° C.), dipropylene glycol monobutyl ether (boilingpoint: 231° C.) and propylene glycol monophenyl ether (boiling point:243° C.)

Examples of the ether include

diethylene glycol dimethyl ether (boiling point: 162° C.), triethyleneglycol dimethyl ether (boiling point: 216° C.), diethylene glycol methylethyl ether (boiling point: 176° C.), diethylene glycol diethyl ether(boiling point: 189° C.), diethylene glycol dibutyl ether (boilingpoint: 255° C.), dipropylene glycol dimethyl ether (boiling point: 171°C.), diethylene glycol monoethyl ether acetate (boiling point: 217° C.),ethylene glycol monobutyl ether acetate (boiling point: 188° C.),1,8-cineole (boiling point: 176° C.), diisopentyl ether (boiling point:171° C.), anisole (boiling point: 155° C.), ethyl benzyl ether (boilingpoint: 189° C.), diphenyl ether (boiling point: 259° C.), dibenzyl ether(boiling point: 297° C.), phenetole (boiling point: 170° C.), dihexylether (boiling point: 226° C.), and the like.

Examples of the other the organic solvent (B1) include

N-methylpyrrolidone (boiling point: 204° C.), N,N-dimethylacetamide(boiling point: 165° C.), formamide (boiling point: 210° C.),N-ethylacetamide (boiling point: 206° C.), N-methylacetamide (boilingpoint: 206° C.), furfural (boiling point: 162° C.), propylene carbonate(boiling point: 242° C.), ethylene carbonate (boiling point: 238° C.),dimethyl sulfoxide (boiling point: 189° C.), sulfolane (boiling point:287° C.), glycerol (boiling point: 290° C.), succinonitrile (boilingpoint: 265° C.), nitrobenzene (boiling point: 211° C.), and the like.

Of these, the organic solvent (B1) is preferably an ester, an alcohol,an ether or a combination thereof, and more preferably a lactone, acarbonate or a compound represented by the following formula (B-1), or acombination thereof.

In the above formula (B-1), R¹ and R² each independently represent ahydrogen atom, an alkyl group having 1 to 4 carbon atoms or an acylgroup having 1 to 4 carbon atoms; R³ represents a hydrogen atom or amethyl group; n is an integer of 1 to 4, in a case where R³ is presentin a plurality of number, a plurality of R³s are each optionally thesame or different.

Examples of the alkyl group having 1 to 4 carbon atoms represented bythe R¹ and R² include a methyl group, an ethyl group, a n-propyl group,an i-propyl group, a n-butyl group, a s-butyl group, an i-butyl group, at-butyl group, and the like. Of these, a methyl group, an ethyl group,and an i-butyl group are preferred.

Examples of the acyl group having 1 to 4 carbon atoms represented by theR¹ or R² include an acetyl group, a propionyl group, a butyryl group,and the like. Of these, an acetyl group is preferred.

The organic solvent (B1) is particularly preferably ethylene glycolacetate, butyl diglycol acetate, isopropyl diglycol, butyl diglycol,isobutyl diglycol, hexyl glycol, 2-ethylhexyl glycol, phenyl glycol,phenyl diglycol, methyl propylene triglycol, propyl propylene diglycol,phenyl propylene glycol, dimethyl triglycol, methyl acetoacetate, ethylacetoacetate, γ-butyrolactone, ethylene carbonate, propylene carbonate,propylene glycol, dimethyl sulfoxide and n-hexanol, and most preferablyethyl acetoacetate, γ-butyrolactone, dimethyl sulfoxide and n-hexanol.

It is to be noted that the organic solvent (B1) may be used incombination of two or more types thereof. The content of the organicsolvent (B1) with respect to the total amount of the solvent (B) is noless than 1% by mass and no greater than 50% by mass, preferably no lessthan 1.5% by mass and no greater than 30% by mass, more preferably noless than 2.0% by mass and no greater than 20% by mass, and still morepreferably no less than 3.0% by mass and no greater than 15% by mass.When the content of the organic solvent (B1) in the solvent (B) fallswithin the above range, drying of the composition for forming a resistunderlayer film in a nozzle can be further prevented, whereby generationof coating defects can be further suppressed.

(B2) Water

The solvent (B) includes the water (B2). The content of the water (B2)with respect to the total amount of the solvent (B) is no less than 1%by mass and no greater than 30% by mass. Due to the solvent (B)including the water (B2) falling within the range specified above,storage stability of the composition for forming a resist underlayerfilm can be improved. The reasons for the improvement of the storagestability of the composition for forming a resist underlayer film due tocontaining the water (B2) in the solvent (B) in an amount falling withinthe range specified above are not necessarily clear. However, it isenvisaged, for example, that modification of silanol groups included inthe composition for forming a resist underlayer film is suppressed,whereby alteration of the film thickness with time is less likely tooccur, and the like.

The content of the water (B2) with respect to the total amount of thesolvent (B) is preferably no less than 1.0% by mass and no greater than25% by mass, more preferably no less than 1.5% by mass and no greaterthan 20% by mass, particularly preferably no less than 2.0% by mass andno greater than 15% by mass, and most preferably no less than 2.5% bymass and no greater than 12 mass %. When the content of the water (B2)in the solvent (B) falls within the range specified above, storagestability of the composition for forming a resist underlayer film can befurther improved.

Also, the content of the water (B2) with respect to 1 part by mass ofthe organic solvent (B1) is preferably no less than 0.1 parts by massand no greater than 10 parts by mass, more preferably no less than 0.2parts by mass and no greater than 5 parts by mass, still more preferablyno less than 0.3 parts by mass and no greater than 3 parts by mass, andparticularly preferably no less than 0.5 parts by mass and no greaterthan 2 parts by mass.

(B3) Alcohol

The alcohol (B3) has a standard boiling point of less than 150.0° C.When the solvent (B) further includes the alcohol (B3), the alcohol (B3)binds to a silanol group of the polysiloxane (A), whereby modificationof the silanol group can be inhibited. Accordingly, an inhibitoryproperty of coating defects, and storage stability of the compositionfor forming a resist underlayer film can be improved.

Examples of the alcohol (B3) include:

monoalcohol solvents such as methanol, ethanol and n-propanol;

partially etherified polyhydric alcohol solvents such as ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, propylene glycolmonomethyl ether, propylene glycol monoethyl ether and propylene glycolmonopropyl ether; and the like.

Of these, propylene glycol monomethyl ether, propylene glycol monoethylether, and propylene glycol monopropyl ether are preferred.

The content of the alcohol (B3) with respect to the total amount of thesolvent (B) is preferably no less than 0% by mass and no greater than50% by mass, and more preferably no less than 10% by mass and no greaterthan 40% by mass. When the content of the alcohol (B3) falls within theabove range, solubility of the polysiloxane (A) in the solvent (B) canbe further improved. It is to be noted that these the alcohol (B3) maybe used in combination of two or more types thereof.

(B4) Other Solvent

The solvent (B) may include (B4) other solvent in addition to theorganic solvent (B1), the water (B2) and the alcohol (B3). Examples ofthe other solvent (B4) include:

ethers such as diethyl ether and tetrahydrofuran;

aromatic hydrocarbons such as benzene, toluene and xylene;

ketones such as acetone, methyl ethyl ketone, methyl-n-propyl ketone,methyl-n-butyl ketone, diethyl ketone, methyl-1-butyl ketone,cyclopentanone and 2,4-pentanedione;

esters such as methyl acetate, ethyl acetate, propyl acetate, isobutylacetate, butyl acetate, ethylene glycol monomethyl ether acetate andpropylene glycol monomethyl ether acetate, and the like.

Of these, esters are preferred, and propylene glycol monomethyl etheracetate is more preferred.

The content of the other solvent (B4) with respect to the total amountof the solvent (B) is preferably no less than 30% by mass and no greaterthan 90% by mass. Also, the other solvent (B4) may be used incombination of two or more types thereof.

(C) Acid Diffusion Controller

The composition for forming a resist underlayer film preferably contains(C) an acid diffusion controller (C). The acid diffusion controller (C)achieves effects of controlling a phenomenon of diffusion of an acidgenerated from a resist film upon exposure through a resist underlayerfilm, and inhibiting an unfavorable chemical reaction in non-exposedregions of the resist film. The form of the acid diffusion controller(C) contained in the composition for forming a resist underlayer filmmay be either a compound form (hereinafter, may be also referred to as“acid diffusion control agent” ad libitum) as described later or a formin which the acid diffusion controller is incorporated as a part of apolymer, or both of these forms.

Examples of the acid diffusion control agent (C) include aminecompounds, amide group-containing compounds, urea compounds,nitrogen-containing heterocyclic compounds, and the like. Of these,amide group-containing compounds are preferred.

Examples of the amine compound include: mono(cyclo)alkylamines;di(cyclo)alkylamines; tri(cyclo)alkylamines; substituted alkylaniline orderivatives thereof; ethylenediamine,N,N,N′,N′-tetramethylethylenediamine, tetramethylenediamine,hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine,2,2-bis(4-aminophenyl)propane,2-(3-aminophenyl)-2-(4-aminophenyl)propane,2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane,2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane,1,4-bis(1-(4-aminophenyl)-1-methylethyl)benzene,1,3-bis(1-(4-aminophenyl)-1-methylethyl)benzene,bis(2-dimethylaminoethyl)ether, bis(2-diethylaminoethyl)ether,1-(2-hydroxyethyl)-2-imidazolidinone, 2-quinoxalinol, N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine,N,N,N′,N″N″-pentamethyldiethylenetriamine, and the like.

Examples of the amide group-containing compound includeN-t-butoxycarbonyl group-containing amino compounds, N-t-amyloxycarbonylgroup-containing amino compounds, formamide, N-methylformamide,N,N-dimethylformamide, acetamide, N-methylacetamide,N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone,N-methylpyrrolidone, N-acetyl-1-adamantylamine, tris(2-hydroxyethyl)isocyanurate, and the like. Of these, N-t-butoxycarbonylgroup-containing amino compounds and N-t-amyloxycarbonylgroup-containing amino compounds are preferred, andN-t-butoxycarbonyl-4-hydroxypiperidine,N-t-amyloxycarbonyl-4-hydroxypiperidine,N-t-butoxycarbonyl-2-carboxy-4-hydroxypyrrolidine andN-t-butoxycarbonyl-2-carboxypyrrolidine are more preferred.

Examples of the urea compound include urea, methylurea,1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea,1,3-diphenylurea, tri-n-butylthiourea, and the like.

Examples of the nitrogen-containing heterocyclic compound includeimidazoles such as 2-phenylimidazole; pyridines; piperazines, and thelike.

Alternatively, as the acid diffusion control agent (C), an onium saltcompound may be also used which is degraded upon exposure to losebasicity that serves as acid diffusion controllability. The onium saltcompound is exemplified by a sulfonium salt compound represented by thefollowing formula (2-1), an iodonium salt compound represented by thefollowing formula (2-2), and the like.

In the above formulae (2-1) and (2-2), R⁴ to R⁸ each independentlyrepresent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxygroup or a halogen atom; Anb⁻ represents OH⁻, R⁹—COO⁻, R⁹—SO₃ ⁻, or ananion represented by the following formula (3); R⁹ each independentlyrepresents an alkyl group, an aryl group or an alkanol group.

Examples of the sulfonium salt compound and the iodonium salt compoundinclude triphenylsulfonium hydroxide, triphenylsulfonium acetate,triphenylsulfonium salicylate, diphenyl-4-hydroxyphenylsulfoniumhydroxide, diphenyl-4-hydroxyphenylsulfonium acetate,diphenyl-4-hydroxyphenylsulfonium salicylate,bis(4-t-butylphenyl)iodonium hydroxide, bis(4-t-butylphenyl)iodoniumacetate, bis(4-t-butylphenyl)iodonium hydroxide,bis(4-t-butylphenyl)iodonium acetate, bis(4-t-butylphenyl)iodoniumsalicylate, 4-t-butylphenyl-4-hydroxyphenyliodonium hydroxide,4-t-butylphenyl-4-hydroxyphenyliodonium acetate,4-t-butylphenyl-4-hydroxyphenyliodonium salicylate,bis(4-t-butylphenyl)iodonium 10-camphorsulfonate, diphenyliodonium10-camphorsulfonate, triphenylsulfonium 10-camphorsulfonate,4-t-butoxyphenyldiphenylsulfonium 10-camphorsulfonate, and the like.

The acid diffusion control agent (C) may be used in combination of twoor more types thereof. The content of the acid diffusion control agent(C) with respect to the total solid content (components excluding thesolvent (B)) in the composition for forming a resist underlayer film ispreferably no less than 1% by mass and no greater than 20% by mass, andmore preferably no less than 2% by mass and no greater than 10% by mass.When the content of the acid diffusion control agent (C) falls withinthe range specified above, pattern developability and the like can befurther improved.

Other Optional Component

The composition for forming a resist underlayer film may contain otheroptional component as needed within a range not leading to impairment ofthe effects of the present invention. The other optional component isexemplified by a surfactant, a storage stabilizer, and the like.

Preparation Method of Composition for Forming a Resist Underlayer Film

The composition for forming a resist underlayer film is prepared by, forexample, mixing the polysiloxane (A), the acid diffusion control agent(C) and as needed other optional component in the solvent (B) at apredetermined ratio. The composition for forming a resist underlayerfilm is used preferably in a state being dissolved or dispersed in anappropriate solvent.

Pattern-Forming Method

The pattern-forming method of the embodiment of the present inventionincludes the steps of:

providing a resist underlayer film on a substrate using the compositionfor forming a resist underlayer film (hereinafter, may be also referredto as “resist underlayer film-providing step”);

providing a resist film on the resist underlayer film using a resistcomposition (hereinafter, may be also referred to as “resistfilm-providing step”);

exposing the resist film by irradiation with a radioactive ray through amask (hereinafter, may be also referred to as “exposure step”);

developing the exposed resist film to form a resist pattern(hereinafter, may be also referred to as “development process”); and

sequentially dry-etching the resist underlayer film and the substrateusing the resist pattern as a mask (hereinafter, may be also referred toas “dry-etching step”).

According to the pattern-forming method, a resist underlayer film thatis superior in the inhibitory property of coating defects can beprovided since the composition for forming a resist underlayer film ofthe embodiment of the present invention is used. In addition, even ifthe composition for forming a resist underlayer film which had beenstored for a long period of time is used, favorable patterns can beobtained. Therefore, the pattern-forming method is responsible forformation of a finer pattern on a substrate.

Resist Underlayer Film-Providing Step

In this step, a resist underlayer film is provided on a substrate usingthe composition for forming a resist underlayer film. Examples of thesubstrate include interlayer insulating films such as wafers coated withan insulating film (e.g., silicon oxide, silicon nitride, siliconoxynitride, polysiloxane, etc.), or with a low-dielectric-constantinsulating film (e.g., Black Diamond (manufactured by AMAT (AppliedMaterials, Inc.)), SiLK (manufactured by Dow Chemical Company), LKD5109(manufactured by JSR Corporation), etc.). A patterned substrate providedwith a wiring gutter (trench), a plug groove (via), or the like may alsobe used as the substrate.

With respect to a method for providing the resist underlayer film, forexample, a coated film of the composition may be provided by coating onthe surface of a substrate and/or other underlayer film, etc., and thecoated film may be subjected to a heat treatment, or both irradiationwith an ultraviolet ray and a heat treatment to allow for hardening,whereby the resist underlayer film can be provided. The method forcoating the composition for forming a resist underlayer film isexemplified by a spin-coating method, a roll coating method, a dippingmethod, and the like. Of these, a spin coating method in which thecomposition for forming a resist underlayer film is sprayed using anozzle is preferred. When this method is used among the foregoings, theeffects of the embodiment of the present invention can be sufficientlyachieved. In addition, the heating temperature is typically 50° C. to450° C., and preferably 250° C. The heating time period is typically 30sec to 1,200 sec, and preferably 45 sec to 600 sec.

In addition, the substrate may be provided beforehand with otherunderlayer film that is different from the resist underlayer filmprovided using the composition for forming a resist underlayer film ofthe embodiment of the present invention (hereinafter, may be alsoreferred to as “other underlayer film”). An antireflective function,flatness of coated films, high etching resistance to fluorine-containinggas such as CF₄, or the like may be imparted to the other underlayerfilm. As the other underlayer film, commercially available products suchas e.g., “NFC HM8005” (manufactured by JSR Corporation), “NFC CT08”(manufactured by JSR Corporation) may be used.

The film thickness of the resist underlayer film is typically no lessthan 5 nm and no greater than 200 nm, and is preferably no less than 10nm and no greater than 100 nm for improving patterning properties.

Resist Film-Providing Step

In this step, a resist film is provided using a resist composition onthe resist underlayer film obtained in the resist underlayerfilm-providing step.

The resist composition is exemplified by a positive or negativechemically amplified type resist composition containing a photoacidgenerating agent, a positive type resist composition constituted with analkali-soluble resin and a quinone diazide based photosensitizing agent,a negative type resist composition constituted with an alkali-solubleresin and a crosslinking agent, and the like. Alternatively, a resistcomposition filtered through a filter having a pore size of about 0.2 μmmay be suitably used. It is to be noted that a commercially availableresist composition may be used as is in the pattern-forming method ofthe embodiment of the present invention.

The coating method of the resist composition is not particularlylimited, and for example, a conventional method such as a spin coatingmethod may be employed. It is to be noted that upon coating the resistcomposition, the amount of the resist composition to be coated isadjusted such that the resulting resist film has a predetermined filmthickness.

The resist film can be provided by prebaking a coated film provided bycoating the resist composition to allow a solvent in the coated film(i.e., a solvent contained in the resist composition) to be volatilized.The temperature employed upon the prebaking may be appropriatelyadjusted according to the type and the like of the resist compositionused, but is preferably 30° C. to 200° C., and more preferably 50° C. to150° C. It is to be noted that other coated film such as a liquidimmersion upper layer film may be further provided on the surface of theresist film. The pre-baking time period is preferably 20 sec to 300 sec,and more preferably 40 sec to 150 sec. The film thickness of the resistfilm is preferably 5 nm to 500 nm, and more preferably 10 nm to 300 nm.

Exposure Step

In this step, the resist film is exposed by irradiation with aradioactive ray through a mask.

The radioactive ray used in this step is appropriately selected fromamong visible light rays, ultraviolet rays, far ultraviolet rays,X-rays, electron beams, γ-rays, molecular beams, ion beam and the likein accordance with the type of the acid generating agent used in theresist composition. Far ultraviolet rays are preferred, and a KrFexcimer laser beam (248 nm), an ArF excimer laser beam (193 nm), an F₂excimer laser beam (157 nm), a Kr₂ excimer laser beam (147 nm), an ArKrexcimer laser beam (134 nm) and extreme ultraviolet rays (13.5 nm, etc.)are more preferred.

Also, the exposure method is not particularly limited, and may becarried out according to a method employed in conventionally well-knownpattern formation. Alternatively, a liquid immersion lithography processmay be also employed.

Development Step

In this step, the resist film exposed in the exposure step is developedto form a resist pattern.

The developer solution for use in the development may be appropriatelyselected in accordance with the type of the resist composition used. Incases where a positive chemically amplified type resist composition or apositive type resist compositions containing an alkali-soluble resin isused, an alkaline aqueous solution of, for example, sodium hydroxide,potassium hydroxide, sodium carbonate, sodium silicate, sodiummetasilicate, ammonia, ethylamine, n-propylamine, diethylamine,di-n-propylamine, triethylamine, methyldiethylamine,dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide,tetraethylammonium hydroxide, pyrrole, piperidine, choline,1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene orthe like may be employed. Also, a water soluble organic solvent, forexample, an alcohol such as methanol or ethanol, as well as a surfactantmay be added in an appropriate amount to the alkaline aqueous solution.

Also, in cases where a negative chemically amplified type resistcomposition or a negative type resist containing an alkali-soluble resinis used, an aqueous solution of an alkali, for example, an inorganicalkali such as sodium hydroxide, potassium hydroxide, sodium carbonate,sodium silicate, sodium metasilicate or aqueous ammonia, a primary aminesuch as ethylamine or n-propylamine, a secondary amine such asdiethylamine or di-n-butylamine, an alcohol amine such as triethylamineor methyldiethylamine, a quaternary amine such as dimethylethanolamineor triethanolamine, a quaternary ammonium salt such astetramethylammonium hydroxide, tetraethylammonium hydroxide or choline,a cyclic amine such as pyrrole or piperidine, or the like may beemployed.

In this step, after the development carried out with the developersolution, washing and drying enable a given resist pattern to be formedcorresponding to the photomask.

Note that carrying out post-baking in this step is preferred before thedevelopment is carried out (i.e., after the exposure carried out in theexposure step) in order to improve the resolution, pattern profile,developability and the like. The post-baking temperature may beappropriately adjusted depending on the type of the resist compositionused, and the like. The post-baking temperature is preferably 50 to 200°C., and more preferably 80 to 150° C. The post-baking time period ispreferably 30 sec to 300 sec, and more preferably 40 sec to 150 sec.

Dry-Etching Step

In this step, the resist underlayer film and the substrate aresequentially dry-etched using the resist pattern

Is as a mask to form a pattern. The dry etching may be effected usingany well-known dry etching apparatus. In addition, depending on theelemental composition of the object to be etched, oxygen atom-containinggases such as O₂, CO, and CO₂, inert gases such as He, N₂, and Ar,chlorine based gases such as Cl₂ and BCl₃, fluorine based gases such asCHF₃ and CF₄, other gases such as H₂ and NH₃ can be used as a source gasin the dry etching. It is to be noted that these gases may also be usedin mixture.

In addition, the pattern-forming method may include a step of removing aresist underlayer film remaining on the substrate after these processes.

EXAMPLES

The present invention will be explained below in detail by way ofExamples, but the present invention should not be construed as beinglimited to the Examples. Methods of the determination of various typesof physical property values are shown below.

Solid Content Concentration of a Solution Containing Polysiloxane (A)

The solid content concentration (% by mass) of a solution containing thepolysiloxane (A) was determined by baking 0.5 g of the solutioncontaining the polysiloxane (A) at 250° C. for 30 min and measuring themass of the solid content in the solution.

Determination of Mw

Mw was determined by gel permeation chromatography (GPC) on the basis ofmono-dispersed polystyrene as a standard using GPC columns (G2000HXL×2;G3000HXL×1; and G4000HXL×1, manufactured by Tosoh Corporation) under ananalytical condition involving a flow rate of 1.0 mL/min and a columntemperature of 40° C. with tetrahydrofuran as an elution solvent.

Synthesis of Polysiloxane (A)

Each monomer used for synthesis of the polysiloxane (A) is shown below.

M-1: tetramethoxysilane, compound represented by the following formula(M-1)

M-2: phenyltrimethoxysilane, compound represented by the followingformula (M-2)

M-3: 4-methylphenyltrimethoxysilane, compound represented by thefollowing formula (M-3)

M-4: methyltrimethoxysilane, compound represented by the followingformula (M-4)

Synthesis Example 1

An aqueous oxalic acid solution was prepared by dissolving 0.55 g ofoxalic acid in 7.66 g of water. Subsequently, a flask charged with 12.95g of the compound (M-1), 5.80 g of the compound (M-2), 3.01 g of thecompound (M-3), and 70.03 g of propylene glycol-1-ethyl ether was fittedwith a condenser and a dropping funnel containing the aqueous oxalicacid solution prepared. Next, after heating the mixture to 60° C. in anoil bath, the aqueous oxalic acid solution was slowly added dropwise topermit a reaction at 60° C. for 2 hrs. After completion of the reaction,the flask containing the reaction solution was allowed to cool, andfitted with an evaporator. Methanol generated by the reaction wasremoved to obtain 49.2 g of a solution containing (A-1) a polysiloxane.The solid content concentration in the resultant solution was 10% bymass. Also, the Mw of the polysiloxane (A-1) was 1,500.

Synthesis Example 2 and Synthesis Example 3

Polysiloxanes (A-2) and (A-3) were synthesized in a similar manner toSynthesis Example 1 except that monomers of the type and amount shown inTable 1 were used. The Mw and the solid content concentration of eachsynthesized polysiloxane are together shown in Table 1.

TABLE 1 (A) Amount Amount Solid content Poly- Type of used usedconcentration siloxane monomer (g) (mol %) Mw (% by mass) Synthesis A-1M-1 12.95 60 1.500 10 Example 1 M-2 5.8 30 M-3 3.01 10 Synthesis A-2 M-115.97 50 2.000 14 Example 2 M-2 12.87 45 M-4 2.08 5 Synthesis A-3 M-119.85 60 2.500 16 Example 3 M-2 7.4 25 M-3 4.61 10 M-4 2.15 5

Preparation of Composition for Forming a Resist Underlayer Film

Each component other than the polysiloxane (A) used for preparation ofeach composition for forming a resist underlayer film is shown below.

(B) Solvent B1-1: Ethyl Acetoacetate

(standard boiling point: 180.8° C.; relative permittivity: 15.9)

B1-2: γ-Butyrolactone

(standard boiling point: 204° C.; relative permittivity: 39)

B1-3: Dimethyl Sulfoxide

(standard boiling point: 189.0° C.; relative permittivity: 48.9)

B1-4: n-Hexanol

(standard boiling point: 157° C.; relative permittivity: 13.3)

B2: waterB3-1: propylene glycol-1-methyl etherB3-2: propylene glycol-1-ethyl etherB3-3: propylene glycol-1-propyl etherB4: propylene glycol monomethyl ether acetate

(C) Acid Diffusion Control Agent

C-1: N-t-amyloxycarbonyl-4-hydroxypiperidine, compound represented bythe following formula (C-1)

C-2: N-t-butoxycarbonyl-4-hydroxypiperidine, compound represented by thefollowing formula (C-2)

C-3: N-t-butoxycarbonyl-2-carboxy-4-hydroxypyrrolidine, compoundrepresented by the following formula (C-3)

C-4: N-t-butoxycarbonyl-2-carboxypyrrolidine, compound represented bythe following formula (C-4)

Example 1

A solution was obtained by mixing 2.10 parts by mass of (A-1) as thepolysiloxane (A), 4.50 parts by mass of (B1-1) as the solvent (B), 7.00parts by mass of the water (B2), 30.00 parts by mass of (B3-1) and 56.35parts by mass of (B4), and 0.05 parts by mass of (C-1) as the aciddiffusion control agent (C). Then, the solution was filtered through afilter having a pore size of 0.2 μm to prepare a composition for forminga resist underlayer film.

Examples 2 to 16 and Comparative Examples 1 to 2

Each composition for forming a resist underlayer film was prepared in asimilar manner to Example 1 except that each component of the type andthe proportion contained as shown in Table 2 was mixed. It is to benoted that “-” denotes that the corresponding component was not used.

TABLE 2 (B) Solvent (C) Acid diffusion (A) Component (B1) Organicsolvent (B2) Water (B3) Alcohol (B4) Other solvent control agent contentcontent content content content content (parts (parts (parts (parts(parts (parts by type by mass) type by mass) type by mass) type by mass)type by mass) type mass) Example 1 A-1 2.10 B1-1 4.50 B2 7.00 B3-1 30.00B4 56.35 C-1 0.05 Example 2 A-1 1.95 B1-2 5.50 B2 5.00 B3-1 25.00 B462.52 C-1 0.03 Example 3 A-1 1.70 B1-3 8.50 B2 3.50 B3-1 20.00 B4 66.28C-1 0.02 Example 4 A-1 2.23 B1-4 7.30 B2 6.50 B3-1 23.00 B4 60.90 C-10.07 Example 5 A-1 2.07 B1-1 7.00 B2 8.30 B3-2 31.00 B4 51.62 C-1 0.01Example 6 A-1 1.83 B1-1 5.00 B2 4.50 B3-3 18.00 B4 70.63 C-1 0.04Example 7 A-2 1.91 B1-1 6.50 B2 5.50 B3-1 28.00 B4 58.01 C-1 0.08Example 8 A-3 2.38 B1-1 7.00 B2 6.50 B3-1 30.00 B4 54.06 C-1 0.06Example 9 A-1 2.03 B1-1 4.40 B2 4.60 B3-1 22.00 B4 66.93 C-2 0.04Example 10 A-1 2.11 B1-1 6.00 B2 8.50 B3-1 27.00 B4 56.36 C-3 0.03Example 11 A-1 2.57 B1-1 3.80 B2 10.30 B3-1 20.00 B4 63.28 C-4 0.05Example 12 A-1 1.89 B1-1 5.50 B2 2.00 B3-1 23.00 B4 67.54 C-1 0.07Example 13 A-1 2.14 B1-1 8.00 B2 14.00 B3-1 35.00 B4 40.84 C-1 0.02Example 14 A-1 2.10 B1-1 2.50 B2 10.00 B3-1 30.00 B4 55.34 C-1 0.06Example 15 A-1 1.99 B1-1 10.00  B2 14.00 B3-1 38.00 B4 35.98 C-1 0.03Example 16 A-3 1.90 B1-1 3.00 B2 3.00 B3-1 12.00 B4 80.06 C-1 0.04Comparative A-1 2.09 — — B2 5.00 B3-1 30.00 B4 72.86 C-1 0.05 Example 1Comparative A-1 1.85 B1-1 6.00 — — B3-1 20.00 B4 72.09 C-1 0.06 Example2

Each of the prepared composition for forming a resist underlayer filmswas evaluated as in the following. The results are shown in Table 3.

Inhibitory Properties of Coating Defects in Providing Coated Film

Each of the prepared compositions for forming a resist underlayer filmwas coated on the surface of a silicon wafer by a spin coating methodusing a coater/developer (manufactured by CLEAN TRACK ACT12, TokyoElectron Limited), and then dried on a hot plate at 220° C. for 60 secto provide each resist underlayer film having a film thickness of 30 nm.Thereafter, the number of coating defects was counted using a a surfacedefect inspection device (KLA2800, manufactured by KLA Tencor).According to the number of the coating defects, evaluation was made as:“A” when the number was no greater than 100; “B” when the number was noless than 101 and no greater than 150; and “C” when the number wasgreater than 150.

Evaluation on Storage Stability (1)

Inhibitory Properties of Alteration of Film Thickness with Time

Each composition for forming a resist underlayer film was coated on thesurface of a silicon wafer using a spin coater under a conditioninvolving a number of revolution of 2,000 rpm for 20 sec, and dried on ahot plate at 250° C. for 60 sec to provide each resist underlayer film.The film thickness of each of the provided resist underlayer films wasmeasured using an optical film thickness meter (UV-1280SE, manufacturedby KLA Tencor) at 50 points, and the average film thickness wascalculated, which was defined as initial film thickness (T0). Moreover,using each composition for forming a resist underlayer film afterheating at 80° C. for 6 hrs, each resist underlayer film was providedsimilarly to the foregoing, and the film thickness of the resultant filmwas measured. The average film thickness was calculated, which wasdefined as film thickness after storage (T). Then the difference (T−T0)between the initial film thickness T0 and the film thickness afterstorage T was calculated, and the proportion of the difference withrespect to the initial film thickness T0, i.e., “(T−T0)/T0” wascalculated as a proportion of film thickness alteration. According tothe calculated value, evaluation was made as: “A” when the value was nogreater than 5%; “B” when the value was greater than 5% and no greaterthan 8%; and “C” when the value was greater than 8%.

Evaluation on Storage Stability (2)

Inhibitory Properties of Coating Defects with Time

Each composition for forming a resist underlayer film was coated on thesurface of a silicon wafer using a spin coater under a conditioninvolving a number of revolution of 2,000 rpm for 20 sec, and dried on ahot plate at 250° C. for 60 sec to provide each resist underlayer film.The number of coating defects of each of the provided resist underlayerfilms was counted using a surface defect inspection device (KLA2800,manufactured by KLA Tencor), which was defined as initial coating defectnumber (D0). Moreover, using each composition for forming a resistunderlayer film after heating at 40° C. for one week, the resistunderlayer film was provided similarly to the foregoing, and the numberof coating defects was counted, which was defined as coating defectnumber after storage (D). Then the difference (D-D0) between the initialcoating defect number D0 and the coating defect number after storage Dwas calculated as an increase in the number of coating defects.According to the calculated value, evaluation was made as: “A” when thevalue was no greater than 100; “B” when the value was no less than 101and no greater than 200; and “C” when the value was greater than 200.

Adhesiveness

Other underlayer film-forming material (“NFC HM8005”, manufactured byJSR Corporation) was coated on a silicon wafer using a spin coater, anddried on a hot plate at 250° C. for 60 sec to provide other underlayerfilm having a film thickness of 300 nm. Each composition for forming aresist underlayer film prepared in the Examples and Comparative Exampleswas coated on the surface of the other underlayer film using a spincoater, and baked on a hot plate at 250° C. for 60 sec to provide eachresist underlayer film having a film thickness of 30 nm. Next, a resistcomposition (“ARX2014J”, manufactured by JSR Corporation) was coated oneach resist underlayer film, and dried at 90° C. for 60 sec to provide aresist film having a film thickness of 100 nm. Furthermore, a liquidimmersion upper layer film-forming material (“NFC TCX091-7”,manufactured by JSR Corporation) was coated on the resist film provided,and dried at 90° C. for 60 sec to provide a liquid immersion upper layerfilm having a film thickness of 30 nm. Then the substrate was subjectedto irradiation under a condition involving 16 mJ/cm² using an ArFexcimer laser irradiation device (“S610C”, manufactured by NikonCorporation), and thereafter heated at 115° C. for 60 sec. Subsequently,a development process was carried out with a 2.38% by mass aqueoustetramethylammonium hydroxide (TMAH) solution for 30 sec to form aresist pattern, a line and space pattern having a line width of 50 nm.The resist pattern formed on the substrate in this manner was observedusing a scanning electron microscope (SEM), and evaluation was made as:“A” when peeling resulting from development did not occur; and “B” whenpeeling resulting from development occurred.

TABLE 3 Storage stability Inhibitory Inhibitory property of property ofInhibitory coating alteration property of defects in of film coatingproviding thickness defects coated film with time with time AdhesivenessExample 1 A A A A Example 2 A A A A Example 3 A A A A Example 4 A A A AExample 5 A A A A Example 6 A A A A Example 7 A A A A Example 8 A A A AExample 9 A A A A Example 10 A A A A Example 11 A A A A Example 12 A A BA Example 13 A A B A Example 14 B A A A Example 15 A A B A Example 16 BA A A Comparative C A A A Example 1 Comparative A C C A Example 2

As is clear from the results shown in Table 3, it was proven that thecomposition for forming a resist underlayer film of the embodiment ofthe present invention enables the number of defects generated inproviding a coated film to be decreased. In addition, it was revealedthat since the composition for forming a resist underlayer film of theembodiment of the present invention is accompanied by a little increasein the number of defects with time, as well as less alteration of thefilm thickness of the provided resist underlayer film with time,superior storage stability is attained. Furthermore, it was revealedthat a resist underlayer film that is superior in adhesiveness to resistfilms can be provided according to the composition for forming a resistunderlayer film of the embodiment of the present invention.

The composition for forming a resist underlayer film of the embodimentof the present invention is superior in an inhibitory property ofcoating defects, and storage stability. Therefore, the composition forforming a resist underlayer film and pattern-forming method can besuitably used in lithography processes for which further miniaturizationhas been demanded.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A composition for forming a resist underlayerfilm, comprising: a polysiloxane; and a solvent comprising: an organicsolvent having a standard boiling point of no less than 150.0° C.; andwater, wherein a content of the organic solvent is no less than 1% bymass and no greater than 50% by mass with respect to a total amount ofthe solvent, and a content of water is no less than 1% by mass and nogreater than 30% by mass with respect to the total amount of thesolvent.
 2. The composition according to claim 1, wherein the standardboiling point of the organic solvent is no less than 180° C.
 3. Thecomposition according to claim 1, wherein the organic solvent is anester, an alcohol, an ether or a combination thereof.
 4. The compositionaccording to claim 1, wherein the organic solvent is a lactone, acarbonate, a compound represented by a formula (B-1), or a combinationthereof,

wherein, in the formula (B-1), R¹ and R² each independently represent ahydrogen atom, an alkyl group having 1 to 4 carbon atoms or an acylgroup having 1 to 4 carbon atoms; R³ represents a hydrogen atom or amethyl group; n is an integer of 1 to 4, in a case where R³ is presentin a plurality of number, a plurality of R³s are each a same ordifferent.
 5. The composition according to claim 1, wherein a relativepermittivity of the organic solvent is 13 or greater and 200 or less. 6.The composition according to claim 1, wherein the solvent furthercomprises an alcohol other than the organic solvent.
 7. The compositionaccording to claim 1, further comprising an acid diffusion controller.8. The composition according to claim 1, wherein the polysiloxane is ahydrolytic condensate of a compound comprising a hydrolyzable silanecompound represented by a formula (i):R^(A) _(a)SiX_(4-a)  (i) wherein, in the formula (i), R^(A) represents ahydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbonatoms, an alkenyl group having 2 to 10 carbon atoms, an aryl grouphaving 6 to 20 carbon atoms or a cyano group, wherein a part or all ofhydrogen atoms included in the alkyl group represented by R^(A) are notsubstituted or substituted by an epoxyalkyloxy group, an epoxy group, anacid anhydride group or a cyano group, and a part or all of hydrogenatoms included in the aryl group represented by R^(A) are notsubstituted or substituted by a hydroxy group; X represents a halogenatom or —OR^(B), wherein R^(B) represents a monovalent organic group; ais an integer of 0 to 3, wherein in a case where R^(A) and X are eachpresent in a plurality of number, a plurality of R^(A)s are each a sameor different and a plurality of Xs are each a same or different.
 9. Thecomposition according to claim 1, wherein the composition is used in amultilayer resist process.
 10. A pattern-forming method comprising:providing a resist underlayer film on a substrate using the compositionaccording to claim 1; providing a resist film on the resist underlayerfilm using a resist composition; exposing the resist film by irradiationwith a radioactive ray through a mask; developing the exposed resistfilm to form a resist pattern; and sequentially dry-etching the resistunderlayer film and the substrate using the resist pattern as a mask.